When you are editing a field group and click the Add New button, from the resulting dialog there is an option to choose from previously created fields (screenshot).
Is that what you did?
If so and the fields are missing from the other groups then that would be a problem, but could you please confirm that is how you added the fields to multiple groups, first?
The problem you mentioned above is abnormal, please check these:
1) Make sure you are using the latest version of Toolset plugins, you can download them here: https://toolset.com/account/downloads/
2) In case it is a compatibility problem, please deactivate all other plugins, and switch to WordPress default theme 2021, deactivate all custom PHP/JS code snippets, and test again
4) If the problem still persists, please provide database dump file(ZIP file) of your website, you can put the package files in your own google drive disk, share the link only, also point out the problem page URLs, I need to test and debug it in my localhost, thanks https://toolset.com/faq/provide-supporters-copy-site/
I can install the duplicator package file and see the problem.
The problem is that, one post type can have only one same post field, you can put the same post field into one field group of same post type.
For example, the single "Prodotto" post: hidden link
If you choose value "Pesature mobili" in custom field "Macro categoria", you should be able to see the custom field "Portata", see my screenshhot Portata.JPG
In your case, you might consider these:
1) Move those special custom fields "Portata" into another custom field groups
2) Edit the "Appears on " option as multiple conditions, see my screenshot